The present invention relates generally to a keypad or keyboard to be used on a portable electronic device and, more particularly, to a keypad to be used with the keypad or keyboard.
In a portable electronic device, such as a mobile phone, a communicator, a personal data assistant (PDA), a portable communications device or the like, a keyboard is usually used to provide a User Interface (UI) between the user and the device. Typically, the keyboard includes a plurality of alphanumerical keypads and/or function keys to allow a user to select a function or to key a value into the device. When the ambient lighting is inadequate, it is essential that the keypads or keys are illuminated so that the user can correctly select the keys.
In a conventional illuminated keyboard, including a keypad and an underlying circuit board, discrete light-emitting devices (LEDs) are surface-mounted on the circuit board to provide illumination to the keypads thereabove. Alternatively, light guides or conduits are used to guide light from one or more light sources on the circuit board to the proximity of the keypads. Conventionally, all the LEDs mounted on the circuit board, as described above, are turned on or off at the same time. Thus, like the light guides, the LEDs for illuminating the keypads cannot be selectively controlled. Furthermore, the surface-mounted LEDs are bulky, and their power consumption is usually high. Because of their bulkiness and high power consumption, these surface-mounted LEDs are not optimal for use in a small portable electronic device.
On a mobile phone, a communicator and any other portable communications device, there is usually an information display panel, such as an LCD panel, for providing information to the user. Typically, one or more softkeys are used to guide the user to operate the device. A softkey has a function displayed at a designated area of the display panel and an associated keypad located outside the display panel adjacent to the designated area. A user can use the associated keypad to choose the function of the softkey. For example, two softkeys are often used in a Nokia mobile phone to assist a user to operate the mobile phone. When the mobile phone is turned on, the initial functions of these two softkeys are shown as xe2x80x9cMenuxe2x80x9d and xe2x80x9cNamexe2x80x9d at their corresponding designated areas. By choosing the xe2x80x9cMenuxe2x80x9d function through the associated keypad, the displayed functions of the two softkeys will change to xe2x80x9cSelectxe2x80x9d and xe2x80x9cExitxe2x80x9d. The xe2x80x9cSelectxe2x80x9d and xe2x80x9cExitxe2x80x9d functions are xe2x80x9crequestsxe2x80x9d to the user, asking the user to choose the next course of action regarding the use of the mobile phone. In this way, the user is provided with a guide to operate the device according to the displayed functions of the softkeys at a given moment. However, this type of softkey has several disadvantages as described below. Because the function of the softkey is shown at a designated area within the display panel, the use of softkeys significantly reduces the available area for displaying other messages on the display panel. Thus, for practical reasons, the number of softkeys is limited to only a few. Moreover, it has been found that some users are confused over the xe2x80x9crequestsxe2x80x9d shown at the designated areas of the display panel and usually cannot relate the requests to the associated keypads. This psychological obstacle is a real problem for traditional softkeys.
It is advantageous and desirable to provide a key wherein the illuminating light source is small and has a low power consumption, and wherein illumination of keys can be selectively controlled. Furthermore, the illuminated key area can include alphabetical letters, numerals, text and/or graphical images to indicate the functions of the key so that the key can be used to replace the softkeys in certain portable electronic devices.
The first aspect of the present invention is an emissive key for use in a keypad or keyboard. The emissive key comprises:
a substrate;
a first electrode layer having a first side and an opposing second side, wherein the first side of the first electrode layer is provided on the substrate;
an organic light-emitting layer having a first side and an opposing second side, wherein the first side of the organic light-emitting layer is provided on the second side of the first electrode layer;
a second electrode layer having a first side and an opposing second side, wherein the first side of the second electrode layer is provided on the second side of the organic light-emitting layer; and
a gas encapsulation layer provided on the second side of the second electrode defining a cavity between the encapsulation layer and the second side of the second electrode layer for containing at least one gaseous species for protecting the light-emitting layer, wherein the first and second electrode layers are operatively connected to a power source in order to activate the organic light-emitting layer.
Preferably, the gaseous species is nitrogen or argon or a combination thererof.
Preferably, the first electrode layer is transparent.
Preferably, the organic light-emitting layer comprises a single pixel to produce light when the organic light-emitting layer is activated, and the key further comprises a masking layer provided on the substrate having clear and opaque areas to form a pattern or symbol, allowing the light produced by the single pixel to pass therethrough.
Alternatively, the organic light-emitting layer comprises a plurality of light-emitting segments which are individually addressable, and the first and second electrode layers comprise a plurality of electrodes for selectively activating the light-emitting segments to form one or more alphabetical letters, symbols or numerals.
Alternatively, the organic light-emitting layer comprises a plurality of light-emitting segments which are individually addressable, and the key further comprises a masking layer provided on the substrate having clear and opaque areas to form a plurality of symbols, allowing the light produced by one or more light-emitting segments to pass through one or more of the symbols, wherein the symbols may include one or more alphabetical letters and numerals.
The second aspect of the present invention is a method of producing an emissive key for use in a keyboard of an electronic device. The method comprises the steps of:
providing a substrate;
providing a first electrode layer on the substrate;
providing an organic light-emitting layer on the first electrode layer;
providing a second electrode layer on the organic light-emitting layer;
providing a gas encapsulation layer on the second electrode defining a cavity between the encapsulation layer and the second electrode layer; and
providing at least one gaseous species in the cavity to protect the light-emitting layer, wherein the first and second electrode layers are electrically connected to a power source in order to activate the organic light-emitting layer.
Preferably, the organic light-emitting layer comprises a plurality of light-emitting segments and the first and second electrode layers comprise a plurality of electrodes for selectively activating the light-emitting segments.
Preferably, the method further comprises the step of providing a masking layer on the substrate, wherein the masking layer has a clear area and an opaque area to form a pattern, so as to allow the light produced by the organic light-emitting layer to pass through the pattern when the organic light-emitting layer is activated.
The present invention will become apparent upon reading the description taken in conjunction with FIGS. 1a to 7.